In a Daily Post article following an investigation in to tombstoning in North Wales, a spokesman for the Royal Society for the Prevention of Accidents, said...

"Go to a place where it’s safe. "Local knowledge and experience is needed. "Heed the warnings along the coast, piers and jetties. "If you see anyone who is at risk in the sea or deep water you should call 999."

In my opinion this is the kind of approach I think will work better. The adrenaline junkie character doesn't like being told they shouldn't do something because someone else (who probably isn't an adrenaline junkie) thinks it's dangerous. It's that feeling that makes them want to try it in the first place. But (unsurprisingly) not even your free-falling, base-jumping, solo-climbing, stuntman WANTS to be hurt. They want to get to that fine line where they get their buzz, but don't get hurt. See the Daily Post for the full article.